Vehicle transmissions use friction clutches to transfer torque between rotating members, and to thereby achieve a desired speed ratio. The clutches of an automatic transmission are typically pressure-controlled, while those of a dual-clutch transmission (DCT) or an automated manual transmission (AMT) are typically position-controlled. Unlike pressure-controlled clutches that are controlled via hydraulic pressure commands, position-controlled clutches are controlled to a specific actuator position via clutch position commands, with each actuator position having a corresponding torque capacity as determined via a calibrated torque-to-position curve or lookup table. Logic translates a commanded clutch position into a corresponding commanded clutch torque. Accurate knowledge of the torque-to-position characteristics of a given clutch is essential to optimum powertrain control.